1. Field of the Invention
This invention generally relates to beverage dispensers with level indicating displays, and more particularly, to level sensing probes used in such dispensers and method of making same.
2. Discussion of the Prior Art
Commercial beverage dispensers of the type having a hollow, insulated body made of stainless steel or other opaque materials with a closable top for direct receipt of beverage from a beverage brewer are known. Such dispensers have a bottom supported above a support surface with a faucet for serving beverage from the hollow body into individual serving cups or the like.
Because the hollow body is made of opaque materials the quantity, or level, of the beverage can not be ascertained simply by viewing the outside of the dispenser, such as is possible with transparent glass carafes and the like. In the past, so-called “sight tubes” mounted on the outside of the dispenser but in fluid communication with the interior were used to provide a visual indication of the level of the beverage within the hollow body. However, these glass tubes are fragile and become stained over time and presented cleaning and hygiene problems.
In order to avoid these problems, it is known to provide an electronic level sensing circuit with a probe within the dispenser body and a visual electronic display mounted to the exterior of the body and responsive to the probe to provide and indication of the beverage level. Such a dispenser is shown and described in U.S. Pat. No. 6,741,180 issued May 25, 2004 to Zbigniew G. Lassota for an invention in “Beverage Dispensing Urn with Electronic Display”, which is hereby incorporated by reference. In the resistive probe used in this dispenser, the resistance between electrically conductive lands on the exterior of a probe body and exposed to the beverage varied depending upon the level of the beverage being was measured to determine the quantity of beverage.
In another patent of Zbigniew G. Lassota, U.S. Pat. No. 7,798,373, issued Sep. 21, 2010 for an invention in an “Airpot Beverage Dispenser with Flow Thorough Lid and Display and Method”, which is hereby incorporated by reference, a capacitive level probe is employed. This capacitive probe is formed by a series of capacitors at different levels that have a total capacitance that depends upon how many of the capacitors are below or above the surface of the beverage. Unlike the resistive the resistive probe, the capacitive plates do not have direct contact with the beverage but sense the beverage indirectly due to changes in dielectric constant.
In order to produce these level sensing probes, it is necessary to provide leads from each of the sensing elements, forming either a capacitor or a resistor within the dispenser body with a sensing circuit located outside of the dispenser body. It is also necessary to hold the sensing elements in a fixed spatial relationship relative to each other and to the bottom of the dispenser body. In the aforementioned patents, the sensing elements are directly mounted to a hollow down tube that extends downwardly from a funnel at the top of the dispenser to convey freshly brewed beverage to the bottom of the dispenser, but the mechanical mounting means that was employed was not always reliable. The funnel is part of a funnel assembly within which the display circuitry is protectively mounted and to which the beverage level display is mounted.
A need exists to make such probes reliably and cheaply and to mount the sensing elements to the probe bodies in a way that is secure, easily accomplished and compatible with contact with the beverage.